Diamond Lapping and
PolishingDiamond Lapping and
Polishing
Due to the exceptional cutting ability of diamond compounds on different ranges of materials, diamond lapping and polishing compounds are becoming more popular in the ceramic and metalworking industry. Diamond compounds, originally developed for finishing of tungsten carbide cutting tools, have proven to be economical for polishing hard materials. Production lapping applications for diamonds are growing in both the flat and center less fields. Moreover, diamond compounds have played a significant role in mirror finishing. Diamond compound applications are growing for the following reasons:
Compared to other abrasive materials now on the market, diamond compounds are harder and stronger. In fact, large diamonds are fragile and easily fractured when they are used for turning and wheel truing operations. However, small shape diamonds are more stable and less subject to fracture as the particles become smaller. Opposite to boron carbide, aluminum oxide, silicon carbide and other abrasives, diamonds do not fracture or become smaller during the process of lapping. The particle size of the diamond powder remains the same during the complete lapping process. Contrasted to the permanence of the diamond particle, which means cutting at a constant rate, other abrasives may fracture during the process and therefore take more time and a larger quantity of abrasives to finish the job. .Top of the page
A diamond compound has a vehicle that supports the diamond particles and applies them properly to the work. Prior to the production of the diamond compound, polishers mixed the diamond powder with olive oil or similar oil vehicles. The problem was that it was time consuming and the oil could not hold the diamonds in a uniform suspension. The oil-based vehicles caused the diamond particles settle down. Due to these difficulties, we developed Sun-Diamond Compound. The compound includes graded diamond particles retained in a durable and uniform suspension. The suspension vehicle has several functions. The major function is to suspend the diamond particles steadily without settling. The vehicle combines coherence and surface pressure to counter the force of gravity. The vehicle is designed to dissolve under the heat of lapping and to lubricate. It is also designed to flush and eliminate metal or ceramic chips produced by the lapping operation.
It is very important to precisely grade diamond particles. Sun Diamond Powder is graded with extreme accuracy to improve the cutting rate, and avoid contamination. The micron grades available from a fraction of micron for fine polishing to larger diamond particles for heavy stock removal. Mixing large and small particles in the same compound will reduce the effectiveness of the compound and increase the polishing time. Sun Diamond Compound are precisely graded to reduce polishing time and increase cutting rate. While polishing using diamond compound, extreme care must be taken to avoid mixing larger graded compounds with finer compounds (avoid contamination). A larger diamond particle could create a deep scratch on a fine finished part in it's last steps of polishing and cause hours of extra work to remove that scratch.
The concentration of a compound refers to the total amount of diamonds in a vehicle and is usually expressed as weight percentage. A compound of 10% concentration includes 10% of diamonds by weight. Concentration varies according to the requirements of the work. Generally speaking, compounds made of small particles have a lower concentration and the larger one has the higher concentration. Top of the page
The shape of the diamond particles are significant to the polishing operation. Most manufacturers produce a blocky shape, somewhat between a cube and a sphere. Our diamond particles will not scratch or embed and has a greater power than a particle with sharp points or edges.
Visual grade identification of Sun-Diamond Compound is achieved by adding liquid color to the vehicle. Liquid coloring is used to exclude solid pigments which might restrain the work of the compound and vehicle, the liquid coloring has no effect towards metals.
Sun-Diamond Compounds are packaged in different quantities. The most popular and recommended way of distributing the compound is by a plastic syringe containing a cylindrical cartridge of Sun-Diamond Compound. The operator can deposit metered amounts of compound on the lapping surface by the syringe dispenser without contaminating the compound. Therefore, any contamination of the compound is almost impossible with the package of cartridge-syringe dispensing unit. Top of the page
There are two ways of dispensing Sun-Diamond Compound. Using a jar dispenser can cause contamination within the compounds. Although Sun-Diamond Compound is recommended for bench use, it should be taken to keep away from any dust or other external material. Another way is using stick applicators which are good for charging small point laps.
To establish a balance among Sun-Diamond Compounds, the materials to be polished and the lap is essential. The lap should be softer than the material rather than harder therefore the compounds will plunge in the lap. In addition, the polishing process using Sun-Diamond Compound is the same as the polishing process for other type of abrasive compounds. Top of the page
The performance of Sun-Diamond Compound depends on the type of lap materials. The materials may be porous or ductile. They can range from the surgical cotton, which is zero in hardness, to a dense cast iron. Generally speaking, the coarser the compound or the more particle to be removed from the compound, the harder lap is needed. The finer the compound, the more ductile lap is preferred because the diamond particles are less embedded in the lap. In addition, the form and the shape of the lap depends on the application. You can obtain the lapping accessories from plates, wheels, bobs, sticks, needles, small shoe attachments, and others.
Diamond abrasives are used for micro or mirror finishing such as to finish dies, molds, hobs, thread guides, wear parts, gages, rolls, and precision parts. The micro-finishing carbide and ceramic cutting tools have been found to be beneficial for lapping. It is worthy to spend a few more minutes to micro finish because it not only performs better but also shows better inspection procedure of lapping. Ordinarily, a micro-finish is not necessarily flat but finish on the order of 1 to 5 micro-inch. Sometimes moderate waviness of the surface are allowed. Top of the page
Metallurgy is to apply the properties of diamond. The first step of metallurgy is to clean-cut the surface rather than to burnish or to smear it. Then, the crystalline structure will be revealed. If you just flow or transfer the surface layers, the crystalline structure will be distorted. Besides, the harder the materials being lapped, the cleaner the cut will be needed. Sun-Diamond Compounds are proved to be the best means of polishing after cutting the fine surface. Top of the page
Improper technique means over-polishing or applying the wrong sizes of diamond compounds or other operations in the lapping procedure. The result of the improper technique is orange peel or light waviness. It is more likely happened on stainless steels than other materials.
Sun-Diamond Compounds are successfully applied in the machine lapping operations. Because of the lasting characteristics of the diamond, we can save more work with diamond compounds than with traditional abrasives. We need to change the equipment to accommodate with the abrasives. In the interest of conservation we can eliminate the serration of a lapping plate or disc or just make it smaller. Top of the page
In terms of total cost-effectiveness, diamond easily outperforms conventional abrasives, such as aluminum oxide and silicon carbide for the following reasons:
Cost; While diamond costs more, ounce per ounce, you must buy substantially larger volumes of conventional abrasives and spend more labor work to achieve the same results produced by diamond. More conventional abrasives require more chemical carrier as well, which consequently increase the cost and it will add to the freight charges. Conventional abrasives have to be mixed on-site with vehicle/carrier to be effective. These messy operations often lead to extra costs in spillage and waste, as well as hidden costs created by improper mixing ratios. Unlike diamond, conventional abrasives require an extra cleaning step. In some applications, both mechanical and an ultrasonic cleaning process are required, driving costs up and productivity down. Sun-Diamond Compounds and Slurries are more environmentally friendly and cost-effective.Top of the page
Distributors, domestic and international dealers
please send email to smg@smg-diamond.com
for
special offers, or call 1-800-SUN-4898 from U.S.A. and
Canada and 1-510-848-8489 from other countries for discounted
prices.
Sun Marketing Group, 1700 Shattuck Ave 315, Berkeley, California 94709, U.S.A.